750-392
CBEX-DE
3-13
Linkage Settings (optional single-point systems)
• Initial adjustment should be made with the motor in full closed position, that is with the shaft on the power
end of the motor in its most counterclockwise position.
• The closer the connector is to the drive shaft, the less the arm will travel - the closer the connector is to the
driven shaft, the farther that arm will travel.
• Over-travel linkage, where used, should not be required in order to extend its spring to the fullest stretch.
For boilers with single-point positioning systems, typical initial linkage settings are as shown below.
Check all linkage for full and free movement of the damper and metering valves and cams. The check can be
done by loosening the linkage at the damper motor connecting arm and manipulating the linkage by hand.
Position the oil and/or gas modulating cams on the jackshaft so that the cam follower assembly is opposite the
first cam adjusting screw. In this position, fuel delivery is at low-fire rate. Tighten the set screws to secure the
cams on the jackshaft.
Initial IFGR linkage settings and adjustments must be established by a qualified Cleaver-Brooks representative.
Improper adjustment could result in unsafe operating conditions. In addition, setup requires simultaneous consider-
ation of air-to-fuel ratios and NOX levels. This can only be accomplished using proper combustion emissions moni-
toring equipment with NOX, O2, CO, and smoke spot measuring capability.
!
Caution
Do not restrict the full travel of the modulating motor.
FIGURE 3-3. Front head linkage option
Front head linkage:
1 - FGR (oil position shown)
2 - Mod motor
3 - Oil metering valve
4 - Air damper
5 - Gas butterfly valve
1
2
3
4
5
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